José Mourinho believes he is singled out for different treatment by those overseeing the game in this country and will vigorously contest the Football Association's improper conduct charge after being sent to the stands during the defeat at Aston Villa.

The Chelsea manager, who is being punished for re-entering the field of play in stoppage time after the referee, Chris Foy, had just cleared a pitch encroachment from both dugouts, has until 6pm on Monday to respond but will submit evidence to the FA contesting the charge. The sanction for the misdemeanour, even as Mourinho's second offence this season, would amount to a fine of around £10,000, though he intends to dispute it as a point of principle.

His objection appears to centre on the FA's decision not to penalise others – including the Aston Villa manager, Paul Lambert, and the substituted home player Gabriel Agbonlahor – for entering the field of play in the initial confusion sparked by Ramires's ugly challenge on Karim El Ahmadi, even though the improper conduct charge refers specifically to his re-entering the field, while signalling for a time-out, moments later.

"Look, you see the charges from the last match and you see that I'm different than everyone else in the eyes of people," Mourinho said. "In their eyes I'm different. That's obvious. It annoys me. I am [treated differently] and I don't know why.

"In relation to English football, nobody, not English or British … nobody working outside this country has defended so much English football as I did during the five years I was working in Italy and Spain. You know my profile as a person: I say what I think and what I feel. I didn't say that because I was expecting to come back one day and wanted nice treatment. That's not the point. Even after Saturday I keep saying English referees are very, very good and I have complete trust in them. Even after Saturday. But it's obvious there's a measure for some and a measure for me. There's a way where I can feel the differences all the time."

Asked whether it was worth fighting the charge given the relatively small fine that would be involved if he accepted the sanction, as he had the £8,000 fine after being sent to the stands against Cardiff City last October, Mourinho said: "Yes. It's the principle. The fine can be £1 but it's the principle. I don't accept the charges. I have to wait until Monday and work out what I will do. For obvious reasons I don't accept the charges."

"We try, we try," Mourinho said. "That's why, on Saturday, we behaved the way we did. Only 'Rami', with that tackle, couldn't control his frustration. The team behaved in a very good way, my bench behaved in a very good way, I behaved in a very good way. We try to keep that. We are fine, we are calm, no problems."